A natural arch carved by a river gave its name to the so-called "Cave of Forgotten Dreams."

A well-preserved medieval village nested on a rocky outcrop and surrounded by a network of cliffs, natural bridges and canyons.

Architect Le Corbusier built his friend a cubist house to match his impressive collection of cubist art.

Ivy-covered Medieval tunnels cut through this charming town in France's Loire Valley.

The largest underground church in Europe.

Historic medieval fortified city in southwest France.

The mental institution where Van Gogh created some of his most famous work now allows guests to walk in the artist's footsteps.

A French valley with forests so lush it was nicknamed "the Small Amazonia of the Pyrenees."

At Monet's beloved home you can still see the Japanese bridge, waterlilies, and weeping willows that were the subjects of some of his most iconic paintings.

This historic island prison holds one of the dungeons from the Count of Monte Cristo even though it is a work of fiction.

Original cabaret handbills, posters, and feline artwork are a purrfect highlight of the Museum of Montmartre.

The eclectic observatory castle of a 19th-century astronomer and explorer.

This French "sea of rocks" is packed with stunning rock formations and its own medieval castle.

Resting on a hill overlooking the coast, these medieval ruins look completely deserted save for their restored chapel.

A sanctuary for wolves in a community which once trembled in fear of the murderous "Beast of Gévaudan."

A place to see how French aristocrats lived in the early 1900s.

French commune at the heart of conspiracies.

This mountain trail inspired Nietzsche to complete his magnum opus.

Series of underground houses inhabited continuously for centuries.

An ancient ossuary in Rouen.

The opulent home that inspired Tintin's Marlinspike Hall and the adventures within.

100-windowed castle turned art gallery, built by one dedicated mason.

The castle was reconstructed to fit Kaiser Wilhelm II's romanticized vision of the Middle Ages.

Bits of architecture from a town destroyed in World War I now decorate this hotel garden.